Differential pressure pneumatic device



Dec. 9, 1969 J. 5-. BALLANTINE 3,482,605

' DIFFERENTIAL PRESSURE PNEUMATIC DEVICE Filed Nov. 13, 1967 2 Sheets-Sheet 1 may, i gum 43,

FIGZZ INVENTOR. JAMES s. BAL'LANT/NE United States Patent 3,482,605 DIFFERENTIAL PRESSURE PNEUMATIC DEVICE James S. Ballantine, P.O. Box 307, Absecon, NJ. 08201 Filed Nov. 13, 1967, Ser. No. 682,403 I Int. Cl. F15b 21/02 U.S. Cl. 137625.66 6 Claims ABSTRACT OF THE DISCLOSURE A differential pressure pneumatic device for operating a valve, switch or the like which has a tappet centrally positioned on the diaphragm, and provided with a blind bore, and has a bleed opening in the side wall of the tappet preferably remote from the blind end to prevent obstruction from particles of dirt. The tappet may be guided to engage a valve stem by a spring spider. The valve stem may consist of eyelets which join together the valve and valve surfaces.

DESCRIPTION OF THE INVENTION The invention relates to programmed controls such as player pianos, or organs, and programmed controls for machine tools, testing equipment, jacquard mechanism and numerous other devices.

It will be evident that the pneumatic operation may be based on vacuum normally applied to both sides of the diaphragm in inactive position, or it may be based upon positive pressure as desired.

The invention is concerned with relieving trouble through clogging of pneumatic differential valves and switches by providing the bleed through the diaphragm in the side wall of a tappet provided with a blind bore.

"Since the bore and the tappet are central, the tendency to tilt the tappet or skew the diaphragm is eliminated, and the air stream is likely to deposit dirt at the end of the blind bore rather than in the bleed. Best results are obtained by locating the bleed toward the diaphragm with respect to the blind end of the tappet.

A further purpose is to provide a crown or ball on the end of the tappet which will engage the valve stem or switch. p

A further purpose is to provide a spring spider to hold the tappet and the valve stem in alignment when they are separated and the tappet moves forward to deliver a hammer blow to the valve stem.

A further purpose is to adjust the seat of the valve, by

joining together the valve and the valve surfaces by eyelets, and locating ballast in the eyelets.

The drawings illustrate a few only of the numerous embodiments in which the invention may appear, selecting the forms shown from the standpoints of convenience 'in illustration, satisfactory operation and clear demonstration of the principles involved.

FIGURE 1 is a central longitudinal section of a differential valve pneumatic device of the invention. FIGURE 2 is an enlarged axial section through the differential valve, showing the parts in operating position. FIGURE 3 is a section of FIGURE 2 on the line -33,-omitting the valve but showing the atmospheric Patented Dec. 9, 1969 machine tools and the like have been prone to malfunctioning, particularly because of dirt which may enter the control chamber from a perforated strip of paper or other suitable material.

It should be recognized that there is a critical relationship between the area of the bleed opening and the area of the tracker bar opening, the tracker bar opening being larger than the bleed opening in many cases in a ratio between 3:1 and 4:1, the 3:1 ratio giving slower action and the 4:1 ratio giving faster action. This critical area relation makes the device subject to impairment if any obstruction occurs in the bleed or any leakage occurs in the pneumatic system. One of the difiiculties is from punchings in new piano rolls and from protruding fibers which become detached from the perforations. Strainers alone have not been suflicient protection. Furthermore, prior art use of adhesive has caused the presence of dirt.

In the prior art the bleed opening has usually been located along the wall of the housing.

The movement of the diaphragm in itself tends to dislodge dirt when the bleed opening is through the diaphragm. Furthermore, by providing the bleed opening at the side wall of the blind bore in the tappet, very favorable conditions are created to dislodge dirt. The bleed opening is preferably located well down from the blind end of the tappet in the side wall.

When the diaphragm is inactive, the tappet should have a clearance from the end of the valve stem of the order of 0.003 to 0.010 inch so that it can gain velocity before it strikes the valve stem. Since the end of the tappet is preferably rounded, it functions as a universal joint if there is slight misalignment.

The valve has valve elements which are secured to opposite sides of it in a very inexpensive manner as by eyelets and the space inside the eyelets is desirably used for control of the weight of the valve.

The differential diaphragm device in the preferred embodiment comprises a differential diaphragm valve 40 which energizes a suitable output device such as a pneumatic operating device. The differential valve comprises a housing 43 which includes a diaphragm housing 44, and a valve housing 45, which are coaxial to provide for interaction as later explained. A diaphragm 46 extends across the diaphragm chamber, dividing it into a control pressure chamber 47, which responds to the pressure in a tracker bar orifice which is connected to the control pressure chamber by a suitable tube through a strainer 53 which is locked in place by an elastic locking ring 54.

At the opposite side of the diaphragm there is a plenum chamber 55 which is connected to a source of vacuum or other suitable pneumatic pressure by a plenum port 56.

Near its outer circumference the one-piece diaphragm 46 has an annular rim 57 which first extends axially and then has at the outside a radially extending annular flange or rim 58 which is axially engaged and sealed between a control pressure housing portion 60, which has an axially extending male sealing ring 61, and a plenum housing portion 62, which has a cooperating annular recess 63, which receives the male sealing rim 61.

It is important in the preferred embodiment to avoid any Iendency to crowd the elastomer of the diaphragm, such as neoprene or other synthetic elastomer, or natural rubber, or a plastic elastomer such as polyvinyl chloride, toward the inside, and in order to cause any crowding of the elastomer of the diaphragm rim to act outwardly, the axial end of the rim 61 is outwardly coned at 64. The axial rim 64, as it extends outwardly, recedes from the opposite wall of the recess 63 and from a plane transverse to the axis.

Control pressure housing portion and plenum housing portion 62 meet each other in an area outside of and below male sealing rim 61, and this, together with the particular dimensions of the diaphragm, sealing rim and recess, serves to control the extent of compression of the annular rim 57 of the diaphragm 46 between male sealing rim 61 and annular recess 63 of the respective housing portions, and keep this part of the diaphragm from being unduly compressed.

At the axis of the diaphragm, and extending through it, there is an opening 65, which receives an open-ended tubular eyelet 66, having a flange portion on the side of the diaphragm adjoining the control pressure chamber. The eyelet 66 extends beyond the diaphragm into the plenum chamber where it telescopes within and makes a forced fit in a tappet which is a tubular blind eyelet 67, having a flange engaging the diaphragm on the plenum chamber side. The side wall of the tubular blind eyelet tappet 67, at the point intermediate between the diaphragm and the blind end 68 of the blind eyelet, has a precisely drilled or punched bleed opening 70 bearing an area relation to the tracker bar orifice so that the tracker bar orifice is three or four times the area of the bleed opening.

In order to make a more efficient diaphragm, the radially inner portion of the diaphragm constitutes a relatively thick circular piston or disk 71 which does not flex, but extends radially outwardly and interconnects integrally by an annular fillet 72, with annular convolutions 73 which are curved at both sides and the top in cross section, and which join the outer rim by an annular fillet 74.

The valve chamber 77 has, at the axis, in position to receive the forward end of the tappet 67, a plenum port 76 which when the valve is open communicates between the valve chamber and the plenum chamber. Surrounding the plenum port 76 at the end of the valve chamber 77 which adjoins the plenum chamber, there is an annular plenum valve seat 78 which is desirably flat and adapted to close the plenum port by closing the valve.

At the opposite side of the valve chamber 77 and opposed to the plenum port, there is an atmospheric port 80, and this is surrounded by an annular atmospheric valve seat 81 which is desirably flat and adapted to be closed by the valve in one position.

In the valve chamber 77 is positioned a valve 82 which has on one face seating material 83, suitably leather or an elastomeric material, which in closed position of the valve engages and closes the plenum port 76 by engaging the plenum valve seat 78 and at the opposite side the valve has valve seating material 84, also suitably of leather or an elastomeric material, which in closed position closes the atmospheric port 80 and engages the atmospheric valve seat 81. The valve materials 83 and 84 are held in place on the valve by an eyelet 85 extending through an opening 86 in the axis of the valve, having a flange 87 at the side holding the valve seating material 84 and receiving a pressed-on eyelet 88 which holds the valve seating material 83 on the side engaging the plenum port 76. The eyelet 85 is elongated and extends into the plenum port to function as a valve stem in line with the tappet. Spiders 90 in the plenum port, preferably spring wire snap rings, guide the outer end of the tappet 67 so that it is in line with the valve stem 85, there being, however, universal joint action and the forward end of the tappet desirably being crowned or forming a portion of a ball to engage the valve stem at the center.

A clearance 89 between the end of the tappet 67 and the end of the valve stem 85 when the diaphragm is retracted permits the tappet to deliver a hammer blow to the valve stem to shift it.

In the preferred embodiment, a hollow space inside the eyelet 85 is filled with a ballast material, such as lead filings 92, which are held in place by an eyelet plug 93 forced in the opening end of the eyelet 85.

The valve housing 45 is made by a housing body 96 which is removably connected to the end of the diaphragm housing and pneumatically seals to it by a packing ring 97. The opposite end of the valve housing 96 is closed by a closure 98 which contains the atmospheric valve seat and the atmospheric port 80, sealing being accomplished by a sealing ring 100.

The valve housing body 96 has at one side an exhaust port 101 which connects in any suitable manner with a pneumatic or other output device. The entire differential valve assembly is held together by a suitable strongback 103 threaded in the ends at 104 and having a bend at 105 opposite the atmospheric port to prevent air noise. The strongback at its ends passes through openings 106 in an attaching plate 107 which has a central opening 108 to engage a boss 110. Suitable nuts hold the strongback against the attaching plate.

In operation of the differential diaphragm valve already mentioned, it will be evident that when the tracker plate orifice is closed by a strip of paper or the like, the vacuum in the plenum chamber is equalized through the bleed opening 70 into the control pressure chamber on the opposite side of the diaphragm. The diaphragm, therefore, is in inactive position as shown in FIGURE 1, and the tappet permits the valve 82 to close on the plenum seat 76. The interior of the pneumatic is open to atmosphere, and the pneumatic is in its retracted position.

When a perforation in the paper or the like is opposite the tracker bar orifice, since the tracker bar orifice is much larger than the bleed opening 70 in the diaphragm, the vacuum in the control pressure chamber is effectively lost, and the control pressure chamber pressure rapidly approaches atmospheric pressure. While this pressure is leaking through the bleed opening 70, since the bleed opening is much smaller, a relatively high pressure is maintained in the control pressure chamber, causing the diaphragm to expand, bringing the tappet first into contact with the valve stem with a hammer blow and then pushing the valve by the valve stem until the atmospheric port 80 of the valve is closed.

When this happens, vacuum from the plenum chamber passes through the open plenum port and through the exhaust port 101 to the pneumatic, and atmospheric pressure collapses the pneumatic and operates the device whatever it is.

The principles of the invention can be applied very effectively to electric rather than pneumatic controls.

FIGURE 7 shows essentially the same diaphragm 46 as in the pneumatic valve, but the tappet 47 in this form is guided by an opening in the chamber wall, the plenum connection being made with an upper switch chamber 146 which communicates with the plenum side of the diaphragm by a plenum port 147.

In this case, the diaphragm chamber member 62 is sealed at the end by a diaphragm housing closure portion 148, there being a packing ring 150. Because of the problem of electrical conductivity, the housing in this case is made of a non-conducting material, such as a plastic rather than metal as in the preferred form of valve.

A switch fixed contact 151 is mounted in the housing by an electrically conducting bolt 152 which passes through the housing to binding nuts 153. The fixed contact element 151 is anchored against turning by a dimple 154 entering a dimple recess 155 in the housing. A movable contact 156 on a suitable spring metal arm is anchored to the housing by an electrically conducting bolt 157 which passes through an opening in the housing and receives binding nuts 158. A dimple 160 in the movable contact engages a dimple recess 161 in the wall of the housing.

Where the paper or other strip closes the tracker bar orifice and the diaphragm is inactive, the tappet 67 allows the movable contact to open under its spring action and the switch is open as shown in FIGURE 7.

When a perforation in the paper or other strip opens the tracker bar orifice, the diaphragm is actuated and the tappet closes the switch.

By moving the bleed opening 70 along the tappet, it is possible to change the effective frequency of the diaphragm and thus to either tune or de-tune the device. By locating the bleed opening closer to the diaphragm and plugging the bore of the tappet at a suitable location behind the bleed opening, it is possible to greatly increase the frequency, and this may be desirable to tune the diaphragm out of range of any possible destructive frequency or to tune the diaphragm at a particularly desirable frequency.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. A differential pneumatic device having a housing, a diaphragm chamber in the housing, a diaphragm extending across the diaphragm chamber, sealed to the wall of the housing and subdividing the diaphragm chamber into a control pressure chamber and a plenum chamber, a control pressure connection to the control pressure chamber, a plenum connection to the plenum chamber, a tappet mounted centrally on the diaphragm and extending into the plenum chamber, and an action actuating device adapted to receive an operative hammer blow from the tappet, characterized in a blind bore extending through the center of the tappet, a bleed opening extending through the side wall of the tappet from the blind bore to equalize the pressure, cause the diaphragm to maintain the tappet straight when deflecting and render the bleed opening self-cleaning.

2. A difierential device of claim 1, in which the bleed opening extends through the side wall of the tappet remote from the blind end of the bore.

3. A differential valve having a housing, a valve chamber at one end of the housing, a diaphragm chamber at the other end of the housing aligned with the valve chamber, a diaphragm extending across the diaphragm chamber, subdividing the same into a control pressure chamber and a plenum chamber and sealed to the housing, a control pressure connection to the control pressure chamber a plenum connection to the plenum chamber, a tappet mounted centrally on the diaphragm and extending into the plenum chamber, there being a blind bore through the center of the tappet open into the control pressure chamber, opposed annular valve seats in the valve chamber on an axis in prolongation of the tappet, a plenum port extending to the plenum chamber through the interior of the valve seat adjoining the plenum chamber, an atmospheric port extending to the atmosphere through the interior of the valve seat opposite to that adjoining the plenum chamber, a valve in the valve chamber having opposed valve elements which close alternatively on the opposed valve seats, a central valve stem on the valve extending into the plenum port in line with the tappet and in one position displacing the valve under the action of the tappet to close the atmospheric port, an exhaust port into the valve chamber, and a spring spider in the plenum port laterally engaging the tappet and the valve stem and keeping them in alignment, characterized in a bleed open ing extending through the side wall of the tappet remote from the blind end of the bore.

4. A difierential valve of claim 3, in which the end of the tappet which adjoins the valve stem is crowned for single point central contact.

5. A differential valve having a housing, a valve chamber at one end of the housing, a diaphragm chamber at the other end of the housing, a diaphragm extending across the diaphragm chamber, subdividing the same into a control pressure chamber and a plenum chamber and sealed to the housing, a control pressure connection to the control pressure chamber, a plenum connection to the plenum chamber, a tappet centrally mounted on the diaphragm extending into the plenum chamber, having a central blind bore extending from the control pressure chamber, a side opening from the plenum chamber into the blind bore of the tappet, opposed annular valve seats in the valve chamber, a valve in the valve chamber having a central stem extending toward the plenum chamber in line with the tappet, there being clearance between the end of the valve stem and the end of the tappet when the diaphragm is retracted and the tappet delivering a hammer blow to the end of the valve stem when the diaphragm is expanding, valve elements on the faces of the valve adjoining the respective seats and eyelets interconnecting the valve elements with the valve and holding the valve elements in place on the valve, one of the eyelets extending through the opening in the valve and the eyelets together forming the valve stem.

6. A differential valve of claim 5, in combination with ballast in the interior of the eyelets adjusting the Weight of the valve.

References Cited UNITED STATES PATENTS 1,829,907 11/1931 McCornack 137l03 2,532,568 12/1950 Myers 251-33 XR 2,487,418 11/1949 Birkemeier et al. 25133 XR 2,652,847 9/1953 Segebarth 137103 3,108,615 10/1963 Cripe 137625.66 3,162,212 12/1964 Leding l37-625.6 3,307,585 3/1967 Schilling et al. l37625.27 XR 3,326,239 6/1967 Saint-Joanis et al. 137-625.66

FOREIGN PATENTS 213,429 2/1957 Australia.

HENRY T. KLINKSIEK, Primary Examiner 

